Atrial versus ventricular secondary tricuspid regurgitation in patients undergoing tricuspid transcatheter edge-to-edge repair: a two-centre european cohort study

Background Secondary tricuspid regurgitation (STR) comprises two distinct phenotypes: atrial STR (ASTR), driven by right atrial dilatation with preserved RV function, and ventricular STR (VSTR), characterised by RV remodeling and leaflet tethering. Whether STR phenotype influences outcomes following T-TEER remains incompletely defined, limiting the ability to tailor patient selection and optimize intervention timing. Aim To compare baseline characteristics, procedural outcomes, and short-term clinical results of patients with ASTR versus VSTR undergoing T-TEER in a real-world, two-centre European cohort. Methods Consecutive patients with severe STR undergoing T-TEER at two tertiary referral centers - were retrospectively analyzed. ASTR was defined as severe STR with preserved LVEF (≥50%), normal RV function, absence of significant left-sided valvular disease, and low pulmonary pressures (sPAP ≤50 mmHg), consistent with a predominantly atrial and annular mechanism. All remaining patients were classified as VSTR. Exclusion criteria were primary (organic) TR and TR attributable to a cardiac implantable electronic device (CIED) lead. The primary endpoint was procedural success (TR reduction to ≤2+) and clinical success at 1 month (TVARC criteria). The secondary endpoint was mortality and HF hospitalization at 3 months. Results A total of 71 patients were included (ASTR n=17, 23.9%; VSTR n=54, 76.1%). Baseline characteristics are summarized in Table 1. Mean age was 75.3±10.7 years; 35.2% were male and 84.5% had atrial fibrillation. ASTR patients exhibited significantly higher LVEF (67.2±9.6% vs 58.0±9.5%, p=0.001), better TAPSE (20.8±3.9 vs 18.0±4.2 mm, p=0.020), and lower sPAP (39.2±6.9 vs 51.4±17.5 mmHg, p<0.0005), with no differences in age, TRI-SCORE, EuroSCORE II, or renal function. The most frequently used device was PASCAL (88.2% in ASTR vs 68.5% in VSTR), followed by Triclip (11.8% vs 31.5%). Procedural success at 24h was comparable between groups (88.2% vs 92.6%, p=0.625), as was 1-month clinical success (88.2% vs 87.0%, p=1.000). ASTR achieved a higher rate of in-hospital TR reduction to ≤1+ (82.4% vs 55.7%, p=0.042). At 3 months, diuretic dose reduction was numerically more frequent in ASTR (44.4% vs 18.8%, p=0.165). Mortality (0% vs 15%, p=0.177) and HF hospitalization (9.1% vs 35.0%, p=0.115) trended favorably in ASTR. Conclusions T-TEER demonstrated comparable procedural success across both phenotypes, confirming suitability regardless of etiology. ASTR patients achieved a significantly higher rate of TR reduction to ≤1+ at discharge (82.4% vs 55.7%, p=0.042). No significant differences were observed in mortality or HF hospitalization. Routine STR phenotyping before T-TEER is strongly encouraged, and prospective validation in larger phenotype-stratified cohorts is warranted.